1. Field of the Invention
The invention relates to a light projection apparatus and its light-mixing module, and more particularly, to a light projection apparatus and its light-mixing module capable of mixing different light beams having their respective colors.
2. Description of the Related Art
FIG. 1 shows a schematic diagram illustrating a conventional illumination system that uses multiple light-emitting diodes as light sources. Referring to FIG. 1, a red light-emitting diode (LED) 102R, a green LED 102G, and a blue LED 102B scatter in an illumination system 100 and are respectively provided on a first heat-dissipating element 104, a second heat-dissipating element 106, and a third heat-dissipating element 108. The emitting light of the red LED 102R passes through a dichroic mirror 112 and a dichroic mirror 114 in succession and then enters a light integrator rod 116. The emitting light of the green LED 102G is reflected by the dichroic mirror 112, passes through the dichroic mirror 114, and then enters the light integrator rod 116. The emitting light of the blue LED 102B is reflected by the dichroic mirror 114 and then enters the light integrator rod 116. Though the above optical configuration may achieve the effect of mixing different light beams having their respective colors and then outputting a combined light beam, the three separate heat-dissipating elements that scatter in the illumination system 100 may excessively widen the horizontal span of the illumination system 100 and expand the occupied space of a projection apparatus as a result.
FIG. 2 shows a schematic diagram illustrating another conventional illumination system that uses multiple light-emitting diodes as light sources. Referring to FIG. 2, a red LED 202R, a green LED 202G, and a blue LED 202B are provided on the same side of a single heat-dissipating element 204. The emitting light of the red LED 202R is reflected by a first reflective mirror 206, passes through a first dichroic mirror 210, reflected by a second dichroic mirror 212, and then enters a light integrator rod 214. The emitting light of the green LED 202G passes through the first dichroic mirror 210 and the second dichroic mirror 212 in succession and then enters the light integrator rod 214. The emitting light of the blue LED 202B is reflected by a second reflective mirror 208, passes through the second dichroic mirror 212, reflected by the first dichroic mirror 210 and then enters the light integrator rod 214. Though such optical configuration may achieve the effect of arranging all LEDs on a single heat-dissipating element 204, the vertical span of an illumination system 200 is lengthen to excessively expand the occupied space of a projection apparatus.